Electrical devices are often connected to other devices via one or more conductors, which are typically wire conductors. For example, wires carrying household electrical current are terminated at a fuse panel or breaker panel located in a basement or other remote location. These panels often require tools to open and may include a means for locking the panel to prevent unauthorized personnel, like children, from entering the panel where high voltages are terminated.
Another example is communication device that provides an interface between a home or office building and a service provider's communication network. The communication network may include a cable network, such as a community television antenna (“CATV”), which may also be used for transporting video, data, voice and other types of information signals. The communication network may also include a telephony network that may comprise plain old telephony service (“POTS”) equipment, or digital subscriber line (“DSL”) equipment. These various types of communication networks typically interface with a user's home or office building at an outdoor interface device.
A network interface device (“NID”) interfaces the service provider's communication with the user's internal home or office wiring. The communication signals typically carried across the interface are low voltage signals that do not pose a safety hazard from personnel contact with an electrical termination at the interface.
However, the same conductors that carry the communication signals may also carry higher voltages. For example in a telephony communication network, a voltage signal is impressed in the same wires that carry a communication signal to cause a telephone being dialed to ring. This is typically referred to as the ringing voltage and is typically ninety volts DC in United States. In a cable system that provides telephony, the NID provides voice signals to a line interface card that couples to the home's or office's internal telephone system wiring. The wiring from the line interface card to the telephony wiring also carries ringing voltage.
Since the housing that encloses the NID equipment is typically plastic and located outside of a house, curious children may open the housing doors to see what is inside. Adults may also open the housing trying to correct an operational problem with their television, telephone or data service.
Conductors that carry ringing voltage typically terminate with a lug such as a ring tongue lug or a spade lug. Installation personnel then connect the lugs to terminal strips using terminal screws. To prevent inadvertent human contact with the head of terminal screws, which could be dangerous if a ringing voltage was impressed on the conductors at the same time as contact, screws with insulated heads are used.
An example of an insulated screw fastener is found in U.S. Pat. No. 5,122,021 to Medal, entitled Encapsulated Fastener and Washer (“'021”). In the '021 patent, a screw with a slotted round head is covered with a plastic cover that provides access to the screw slot. A hexagonal shape is molded into the plastic cover to facilitate the use of a wrench or nut driver in tightening the screw. The plastic cover edges extend slightly above the top of the screw head to block a finger from contacting the otherwise exposed screw head. Thus, the flat screw top is slightly recessed into the plastic cover.
Although the arrangement described in the '021 patent provides some protection from contact with the screw head, a determined child with small, fleshy finger tips could press the screw end and contact the metallic flat screw head surface. Thus, there is a need in the art for a terminal fastener that further reduces the possibility that contact with the metallic fastener can occur, either inadvertently or deliberately.